In a wireless communication system wherein a plurality of mobile battery powered devices employ wireless techniques in order to communicate with each other, extending the battery life i.e., extending the time period between battery recharges is of key importance to continued communications. As will be appreciated, various subsystems of a battery powered device may place heavier demands upon battery resources than others. For example, when the battery powered device employs a wireless transceiver to transmit and receive data, said transceiver typically consumes significant quantities of battery power, and hence, adversely impacts overall battery life. In order to increase the overall battery life of such devices, it would be extremely advantageous to provide a power management methodology for use in association with the wireless communication system that is capable of minimizing the power consumed by such battery powered devices.
Unfortunately, problems with data delivery begin to surface as power management schemes permit devices to alternate between various modes of operation, such as, for example, either an "active" or a "sleep" mode of operation. As will be appreciated, when a communicating device enters the sleep mode of operation, only the basic device functions such as system clock, timers, interrupts, etc. are operational. During the sleep mode, power to the rest of the device hardware is turned off. In particular, the wireless transceiver portion of an asleep device receives no power, thus, the device can neither transmit nor receive information, and therefore cannot perform any communications activities. Under the above scenario, the channel access performance of an asleep device is severely impaired due to its inability to communicate.
It would be extremely advantageous therefore to provide a power management and packet delivery method for use in a wireless LAN that assures packet delivery and improves the channel access performance of asleep devices.